Hi Vasile, Thanks for your feeback. Indeed, this is a naive PCB I have here, but I'm afraid I can't do more by myself...
> > I am appreciating your enthusiasm, however the shield you've designed it > hasn't too much ability of shielding. > "shield", is the sense of a "physical" shield over the main board. > > If your need carrying PWM signals from one board to other, where both or > only one board has also analogic areas, you must be very carefull. You need > two layers and ground planes on both layers connected through a number of > vias. > Original Arduino's shields have 2 GND pins, as for here. I can't build real two layers PCB at home. Red lines are for bridges (or vias). > > If your application is pure digital, both boards without any analogic area, > then shielding is not important. > OK > > If the PWM is used for generating a clean analogic signal after a > filter, could be a serious problem (clean PWM filtering with first order > filters is impossible, no matter what you have seen on the enthusiastics > websites; clean means lower than 5mV ripple). > > Learn to avoid in your design 90 degree direction changes in your routes as > a general rule. If you have two layers, use traces equaly on both > layers. Avoid multiple layer changes on clocks, PWMs and other agressing > signals. Designing a PCB it's like programming. You can't do it well if you > don't do it continously...Biggest problems start on 8-12 layers, but two > layers an a PIC it's a good start. > Yeah you're right. I'm not continuously building PCB, but I'm continuously trying to sometime build some :) I'm very respectful for people who knows how to do this, like Richard. His Jaluino design is very clean, yet very easy to build. I'll think more about this, and may provide another PCB for this "Styx" shield. The problem is despite the fact there aren't many components, you have to map pins so lots of cross. I may also re-map pins to a more natural layout. Thanks. Seb > > On 9/10/09, Sebastien Lelong <[email protected]> wrote: > >> Hi guys, >> >> >> I've committed Jaluino PCB & schematic template for Eagle (see >> http://code.google.com/p/jallib/source/browse/trunk/project/jaluino/schematics/jaluino_shield_template_eagle.zip). >> From this, I tried to create a shield that could act as a layer, an >> intermediate, between Jaluino shields and Arduino shields. The idea is to >> plug this intermediate shield onto Jaluino board, then plug an original >> Arduino shield on top of this. >> >> Attached are pictures of: >> >> - schematic: with mapping between Jaluino & Arduino pins. For PWM >> channels, one is taken from RC2/CCP1, another is taken either from RC1/CCP2 >> or RB3/CCP2. RC1 and RB3 are multiplexed, so you can choose which of these >> two pins will carry PWM. Using this approach, it may increase compatibility >> (still only 2 PWM channels will be available, but for one, you can choose >> where). As for analog pins, RA3/AN3 is mapped with AREF. Other mappings are >> quite explicit. I'm open to suggestions ! >> >> - PCB: the resulting PCB. Green aeras are considered as blue tracks (but >> couldn't make them blue...). Quite a lot of vias, not that beautiful, >> sorry... >> >> >> Finally, I had a hard brainstorming (not just with myself this time), to >> find a name for this shield: "Styx". So this is Jaluino "Styx" shield. Why ? >> Well... Well in Greek Mythology, Styx is the river between Earth and >> Underworld, a clear frontier between two worlds. I hope this illustrates as >> good as possible the main purpose of this shield. Defining which part is >> Earth, which part is Underworld in our case is left to readers' objectivity >> :) >> >> >> http://en.wikipedia.org/wiki/Styx for more... >> >> >> >> Cheers, >> Seb >> -- >> Sébastien Lelong >> http://www.sirloon.net >> http://sirbot.org >> > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "jallib" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/jallib?hl=en -~----------~----~----~----~------~----~------~--~---
